Experimental Investigation of Propeller Wake Wash

螺旋桨尾流洗流实验研究

• 批准号: RGPIN-2016-03905
• 负责人: Veitch, Brian
• 金额: $ 2.11万
• 依托单位: Memorial University of Newfoundland
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=708573
• 关键词: Experimental; Investigation; Propeller; Wake; Wash

Navigation in ice-covered waters requires that vessels be capable of operating in natural ice conditions, such as broken pack ice and intact level ice. Conventional ice-breaking operations rely largely on the mass and power of the vessel to break through ice. The ship's structure must be correspondingly strong. Recent innovations in marine propulsion technology have provided opportunities to use propeller wake wash as another means to break, clear, and otherwise manage ice. Icebreaking operations employing propeller wake wash can reduce significantly the ship structure-ice interaction involved in conventional icebreaking, thereby reducing the likelihood of structural damage and accidental spills of fuel or cargo, and improving the operation's energy efficiency. Propeller wake wash has been used for years by mariners to clear broken ice from shipping channels, but it has only been since the advent of azimuthing types of propulsors that it has been incorporated into operations by design. At present, the design is done on an ad hoc basis as there is limited fundamental understanding of how the wake wash develops downstream of the propeller and subsequently interacts with sea ice at the free surface. The proposed research will address this knowledge gap. The proposed research will characterize propeller wake wash in terms of the 3-D fluid velocity field downstream, including the velocity field at the free surface. The characterization will be based on laboratory experiments. Experiments will be done in the tow tank at Memorial University's Ocean Engineering Research Centre. Experiments will focus first on the propeller wake wash in the absence of ice, and then on the interactions of the wake wash and ice. The focus of interest in terms of ice features will be on pack ice. A semi-empirical mathematical model will be developed of the downstream wake, and the interaction between the flow at the free surface and its interaction with pack ice. The model of the wake wash field will include mean velocities, as well as of its variability throughout the downstream wake. It will be tested against field observations of ships in ice, as the final experimental element of the proposed work. The wake model will predict the downstream surface velocity field in terms of key factors: delivered power, depth of submergence of the propeller, and inclination angle of the propeller to the free surface. When coupled to the ice interaction model, the model should predict how wake wash can clear pack ice en masse downstream from the propeller. This will be useful for designers and operators, such as commercial shipping, the Coast Guard, Navy and others who navigate in ice in connection with transportation, exploration and defense. The proposed research covers a 5 year time span. Four Master's students will work on this program. All graduate students will be in a thesis-based degree program.

在冰覆盖的水域中导航要求容器能够在自然冰条件下进行操作，例如碎冰块和完整的水平冰。传统的破冰行动在很大程度上依赖于船只的质量和力量来突破冰。船的结构必须相应地很强。海洋推进技术的最新创新提供了使用螺旋桨唤醒的机会，作为破坏，清除和以其他方式管理冰的另一种手段。使用螺旋桨洗涤器的破冰操作可以大大减少与传统破冰有关的船舶结构 - 冰的互动，从而减少结构性损坏和意外燃料或货物的意外溢出的可能性，并提高操作的能源效率。水手已经使用了多年的螺旋桨唤醒，以清除运输频道中破裂的冰，但是自从Azimuthing类型的推进器出现以来，它才通过设计将其纳入操作中。目前，设计是在临时的基础上进行的，因为对尾洗的方式的基本了解有限，并随后与自由表面的海冰相互作用。拟议的研究将解决这一知识差距。 拟议的研究将根据下游的3-D流体速度场（包括自由表面的速度场）来表征螺旋桨唤醒。表征将基于实验室实验。实验将在纪念大学海洋工程研究中心的拖车坦克中进行。在没有冰的情况下，实验将首先集中在螺旋桨唤醒上，然后将其相互作用。在冰功能方面，感兴趣的重点将放在包装冰上。将开发出下游唤醒的半经验数学模型，以及自由表面的流量与包装冰的相互作用之间的相互作用。唤醒场的模型将包括平均速度，以及在整个下游唤醒过程中的可变性。它将针对冰上的船只的现场观测来进行测试，这是拟议工作的最终实验元素。尾流模型将通过关键因素来预测下游表面速度场：传递的功率，螺旋桨浸没的深度以及螺旋桨倾斜角度与自由表面的倾斜角。当与冰相互作用模型结合使用时，该模型应预测尾洗可以如何清除螺旋桨下游的冰层。 这对于设计师和运营商，例如商业运输，海岸警卫队，海军以及其他与运输，勘探和防御有关的冰上导航的人都会有用。 拟议的研究涵盖了5年的时间范围。四个硕士学生将在此计划上工作。所有研究生将参加基于论文的学位课程。